JP2014136807A - Apparatus and method for producing metal powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for producing metal powder, which enable metal powder in a dry state to be obtained from molten metal powder at lower cost by means of a rapid cooling mechanism using a cooling medium such as water.SOLUTION: A jet burner 12 jets a frame jet 21 to a molten metal 1 or a metal wire supplied by supply means 11. Cooling means 13 jets a cooling medium 22 toward a molten metal powder obtained by jetting of the frame jet 21 or a frame jet 21a including the molten metal powder. The cooling means 13 jets the cooling medium 22 in such a manner that the metal powder right after being cooled by the cooling medium 22 maintains a temperature higher than the boiling point of the cooling medium 22. The cooling medium 22 consists of a liquid or a liquid mist having a temperature in the vicinity of the own boiling point.

Description

  The present invention relates to a metal powder manufacturing apparatus and a metal powder manufacturing method.

  Conventionally, as a method for obtaining an amorphous metal powder by increasing the cooling rate during atomization, a water atomization method (for example, see Patent Document 1) in which water is injected to pulverize molten metal, gas atomization, and high-speed rotating water flow There is a SWAP method (for example, refer to Patent Document 2 or 3) in combination with water atomization using.

  On the other hand, there is one that obtains a spherical and fine metal powder by injecting a frame jet onto a molten metal or metal wire using the principle of the atomizing method (see, for example, Patent Document 4 or 5). In this method, molten metal powder refined by a frame jet is cooled and solidified during flight to form a spherical metal powder, and is not rapidly cooled to obtain an amorphous metal powder.

  In the field of thermal spraying, a method for forming an amorphous coating by injecting a gas or a liquid mist mixed gas toward a flame containing material particles has been developed (see, for example, Patent Document 6 or 7). However, in the case of thermal spraying, since the material particles are metal powder, the principle is different from the atomizing method using molten metal or metal wire as a raw material, and the thermal spraying technique cannot be applied to the atomizing method as it is. .

JP 2006-63357 A Japanese Patent Laid-Open No. 5-148516 JP 2010-90421 A JP-A-10-176206 International Publication WO2012 / 157733 JP 2008-174784 A JP 2010-22895 A

  In the water atomization method described in Patent Document 1 capable of rapid cooling and the SWAP method described in Patent Documents 2 and 3, since a large amount of water is used, the obtained metal powder is mixed with water to form a slurry. Therefore, dehydration and drying processes are required. For this reason, there existed a subject that the installation cost for introduce | transducing a dehydration drying apparatus and the running cost for driving | running it increased. Moreover, the expensive high-pressure pump for injecting water at high speed is also required, and there is a problem that the equipment cost increases. Moreover, about the powder with high possibility of oxidation, since it became exposed to water for a long time, oxidation became remarkable and a reduction | restoration process may be needed, There also existed a subject that the metal which can respond was limited.

  The present invention has been made by paying attention to such a problem, and can obtain a dry metal powder at a lower cost by using a rapid cooling mechanism using a cooling medium such as water for the molten metal powder. An object of the present invention is to provide a metal powder production apparatus and a metal powder production method.

  In order to achieve the above object, a metal powder manufacturing apparatus according to the present invention is a metal powder manufacturing apparatus for obtaining metal powder using the principle of the atomizing method, and supplies molten metal or metal wire. A supply means; a jet burner for injecting a flame jet to the molten metal or the metal wire supplied by the supply means; and a molten metal powder obtained by injection of the flame jet, or the molten metal powder. And cooling means for injecting a cooling medium toward the frame jet.

  A metal powder manufacturing method according to the present invention is a metal powder manufacturing method for obtaining a metal powder using the principle of an atomizing method, in which a flame jet is jetted onto a molten metal or a metal wire, and the frame A cooling medium is jetted toward the molten metal powder obtained by jet jetting or the frame jet containing the molten metal powder.

  The method for producing a metal powder according to the present invention can be preferably carried out by the metal powder production apparatus according to the present invention. A metal powder manufacturing apparatus and a metal powder manufacturing method according to the present invention include a molten metal powder obtained by jetting a flame jet, or a molten metal by jetting a cooling medium toward the flame jet including the molten metal powder. The powder can be cooled rapidly and a metal powder can be obtained. At this time, an amorphous metal powder can be obtained by adjusting the temperature and amount of the cooling medium to be injected. Even if the diameter of the molten metal powder is relatively large, the metal powder in an amorphous state can be obtained by adjusting the temperature and amount of the cooling medium to be injected. Since the molten metal is pulverized by the frame jet or the metal wire is melted and pulverized, a spherical metal powder can be obtained.

  The metal powder manufacturing apparatus and the metal powder manufacturing method according to the present invention are in a dry state by adjusting the temperature and amount of the cooling medium to be injected so that the cooling medium does not remain as a liquid after cooling the molten metal powder. The metal powder can be obtained. For this reason, the process of spin-drying | dehydration and drying is unnecessary, and the cost concerning the process can be reduced. Further, the high-pressure pump used in the water atomization method and the SWAP method is not necessary, and the equipment cost can be reduced. As described above, the metal powder production apparatus and the metal powder production method according to the present invention can obtain a metal powder by rapidly cooling the molten metal powder at a lower cost than the water atomization method and the SWAP method. it can.

  In the metal powder manufacturing apparatus and the metal powder manufacturing method according to the present invention, it is preferable that the cooling medium can be directly injected toward the molten metal powder obtained by injection of a frame jet if the cooling medium can be directly injected. In this case, the molten metal powder can be easily and rapidly cooled, and the cooling rate can be easily controlled. Further, when the molten metal powder obtained by the flame jet is distributed as it is inside the flame jet, the cooling medium may be jetted toward the flame jet containing the molten metal powder. As a result, the molten metal powder can be indirectly cooled by cooling the flame jet, or the molten metal powder can be directly cooled together with the flame jet. In any case, the molten metal powder can be rapidly cooled. .

  Unlike the thermal spraying, the metal powder manufacturing apparatus and the metal powder manufacturing method according to the present invention can use a molten metal instead of a solid metal powder. Also, since it is necessary to pulverize the molten metal into powder or melt the metal wire into powder, the speed of the flame jet is important, and it is necessary to heat until the raw material is softened with flame like spraying Absent. For this reason, in this invention, it is necessary to make it larger than the flame speed of a general thermal spraying, for example, the speed close | similar to a supersonic speed or a sound speed. Also, in the case of thermal spraying, it is necessary to solidify the sprayed material after adhering it to the base material, so the sprayed material in the flame cannot be cooled below its melting point or softening temperature. The metal powder manufacturing apparatus and the metal powder manufacturing method according to the invention are not limited as long as the metal powder can be obtained.

  Further, in the case of thermal spraying, it is necessary to heat the powder used for thermal spraying and attach it to the base material, so that the upper and lower limits are imposed on the heated temperature. In addition, the distance from the nozzle tip of the thermal spray to the base material is usually 300 mm or less, and during the time passing through this distance, the temperature is raised to near the semi-molten state and collided with the base material to be below the crystallization temperature. It is necessary to perform cooling up to. For this reason, there are restrictions on the amorphization by thermal spraying. The powder material is also limited to a special metallic glass-based alloy that easily becomes amorphous. In the case of thermal spraying, when cooling with water, oxidation of the base material due to moisture, oxidation during cooling in the atmosphere, and the like occur, and therefore nitrogen is mainly used as the cooling medium. On the other hand, since the metal powder manufacturing apparatus and the metal powder manufacturing method according to the present invention can manufacture metal powder in a sealed chamber, even if water is used as a cooling medium, oxidation by the atmosphere does not occur. Moreover, there is no adverse effect due to excessive cooling. Further, by controlling the amount of water so as to maintain the temperature at which saturated water vapor is generated, it is possible to obtain a dry amorphous powder, and it is not necessary to limit the raw material to an alloy that easily becomes amorphous.

  In the metal powder manufacturing apparatus and the metal powder manufacturing method according to the present invention, the cooling medium is preferably composed of a liquid or a liquid mist. In particular, the cooling medium is preferably composed of a liquid or a liquid mist having a temperature near its boiling point. In this case, since the injected cooling medium takes heat of vaporization when heated and evaporated by the molten metal powder or the frame jet, the molten metal powder can be efficiently cooled. By making the cooling medium a liquid mist, the contact area with the molten metal powder or the flame jet can be increased, and evaporation can be promoted to increase the cooling rate. Further, by setting the cooling medium to a temperature in the vicinity of its boiling point, the time for which the cooling medium is heated to the boiling point can be shortened, and the cooling rate can be further increased. In order to obtain a cooling medium in the vicinity of the boiling point, for example, a method of directly heating the cooling medium, a method of spraying a high-pressure liquid cooling medium with a nozzle, and heating with a Joule-Thomson effective heating method, etc. Can be used. The liquid or liquid mist of the cooling medium is preferably made of water, liquid nitrogen, liquefied carbon dioxide gas, or the like. When the cooling medium is made of liquid nitrogen or liquefied carbon dioxide, a dried metal powder can be obtained even if the molten metal powder is cooled to room temperature. A special antioxidant may be used for the cooling medium. In this case, the oxidation of the powder can be suppressed, and the powder can be easily stored and handled in the subsequent steps.

  In the metal powder manufacturing apparatus according to the present invention, the cooling means preferably injects the cooling medium so that the metal powder immediately after cooling with the cooling medium maintains a temperature higher than the boiling point of the cooling medium. In the method for producing a metal powder according to the present invention, it is preferable that the cooling medium is injected so that the metal powder immediately after cooling with the cooling medium maintains a temperature higher than the boiling point of the cooling medium. In this case, the dried metal powder can be obtained reliably.

  In the metal powder manufacturing apparatus according to the present invention, the jet burner has an acute angle to the molten metal or the metal wire with a substantially uniform jet pressure without a gap along the outer periphery of the molten metal or the metal wire. The frame jet is jetted from the periphery of the molten metal or the metal wire so as to collide with the molten metal, and the cooling means is formed from the outside of the frame jet injected to the molten metal or the metal wire. It is preferable to inject a cooling medium. The method for producing a metal powder according to the present invention is such that the frame jet collides with the molten metal or the metal wire at an acute angle with a substantially uniform jet pressure without a gap along the outer periphery of the molten metal or the metal wire. It is preferable that the flame jet is jetted from around the molten metal or the metal wire, and the cooling medium is jetted from outside the flame jet that is jetted to the molten metal or the metal wire. In this case, uniform atomization can be performed on the molten metal or the metal wire, and a fine and uniform spherical metal powder can be obtained. Further, the cooling efficiency by the cooling medium can be increased, and the cooling rate can be increased.

  In the metal powder manufacturing apparatus according to the present invention, the cooling means preferably injects the cooling medium from the outside and / or the inside of the frame jet containing the molten metal powder. In the method for producing metal powder according to the present invention, it is preferable that the cooling medium is sprayed from the outside and / or the inside of the frame jet containing the molten metal powder. When spraying from the outside, the cooling medium is preferably liquid mist. Further, when the cooling around the center of the frame jet is insufficient only by the cooling from the outside, the cooling medium may be injected inside the frame jet. In this case, in order to efficiently supply the cooling medium to the inside of the frame jet flowing at an ultra-high speed, the high-pressure injection of the cooling medium may be performed not by the mist but by the straight solid nozzle of the stream. Furthermore, the surface area of the cooling medium can be increased by supplying the cooling medium from two or more places rather than supplying the cooling medium from one place, and by focusing and making the cooling medium mist at the focal point. It can be further enhanced.

  ADVANTAGE OF THE INVENTION According to this invention, the metal powder manufacturing apparatus which can obtain the metal powder of a dry state using the rapid cooling mechanism using cooling media, such as water, molten metal powder, and manufacture of metal powder at lower cost A method can be provided.

It is a side view which shows the manufacturing apparatus of the metal powder of embodiment of this invention. Scanning electron micrographs (a), (c), and (e) of the metal powder obtained using the Fe-10% Cr-8% P-2% C alloy as a raw material by the metal powder manufacturing apparatus shown in FIG. SEI images, (b) (d) (f) COMPO images. It is a graph which shows the particle size distribution of the metal powder obtained by using the Fe-10% Cr-8% P-2% C alloy as a raw material with the metal powder manufacturing apparatus shown in FIG. It is a graph which shows the X-ray-diffraction result of the metal powder obtained by using the Fe-10% Cr-8% P-2% C alloy as a raw material with the metal powder manufacturing apparatus shown in FIG. It is a graph which shows the X-ray-diffraction result for every particle size of the metal powder obtained by using the Fe-10% Cr-8% P-2% C alloy as a raw material with the manufacturing apparatus of the metal powder shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 5 show a metal powder manufacturing apparatus and a metal powder manufacturing method according to an embodiment of the present invention.
As shown in FIG. 1, the metal powder manufacturing apparatus 10 includes a supply unit 11, a plurality of jet burners 12, and a cooling unit 13.

  The supply means 11 consists of a container for storing the molten metal 1. The supply means 11 has a pouring nozzle 11a communicating with the inside at the center of the bottom surface. The supply means 11 is configured to allow the molten metal 1 stored therein to flow downward from the pouring nozzle 11a.

  Each jet burner 12 is disposed below the supply means 11 at a rotationally symmetric position with respect to the downstream 1 a of the molten metal 1 from the pouring nozzle 11 a. Each jet burner 12 is arranged to be able to inject the frame jet 21 obliquely downward from the periphery of the downstream 1 a of the molten metal 1. Each jet burner 12 causes the flame jet 21 to collide with the molten metal 1 at an acute angle with substantially uniform jet pressure without a gap along the outer periphery of the downstream 1a of the molten metal 1 at the same pressure and speed. It is configured to inject. Thereby, each jet burner 12 concentrates and jets the flame jet 21 at one point of the drooping downstream 1a. Each jet burner 12 is configured such that a molten metal powder can be formed by pulverizing the molten metal 1 by injecting a frame jet 21 to the downstream 1 a of the molten metal 1. Each jet burner 12 ejects the frame jet 21 at a supersonic speed or a speed close to the sonic speed.

  The cooling means 13 has a plurality of cooling nozzles 13 a that can inject the cooling medium 22. The cooling medium 22 is made of water, liquid nitrogen, liquefied carbon dioxide gas, or the like. Each cooling nozzle 13a is disposed at a rotationally symmetrical position below each jet burner 12 with respect to one frame jet 21a in which each frame jet 21 concentrates at one point and flows downward. Each cooling nozzle 13a is configured to inject a cooling medium 22 obliquely downward from one frame jet 21a containing molten metal powder toward the frame jet 21a. Each cooling nozzle 13a is configured to be able to inject the cooling medium 22 within a predetermined range along the flow direction of the frame jet 21a so that the cooling medium 22 contacts the outer peripheral surface of the frame jet 21a without a gap.

  The cooling means 13 can inject the liquid cooling medium 22 in a straight water flow, shower form, mist form or the like. The cooling means 13 may be configured to inject the cooling medium 22 in different states, such as a straight water flow and a mist shape, for each cooling nozzle 13a. The cooling means 13 is a cooling device having a temperature near the boiling point by directly heating the cooling medium 22 or spraying a high-pressure liquid cooling medium 22 with a nozzle and heating it by the Joule-Thomson effect. The medium 22 can be ejected. The cooling means 13 can be jetted by adjusting the temperature and amount of the cooling medium 22 so that the metal powder immediately after cooling by the cooling medium 22 maintains a temperature higher than the boiling point of the cooling medium 22.

  In a specific example, each of the jet burners 12 is a small-sized jet burner manufactured by HARD INDUSTRY CO., LTD. Capable of injecting the frame jet 21 at a speed higher than the speed of sound. The jet burner 12 is composed of four units, and the cooling nozzles 13a are composed of four units.

  The method for producing metal powder according to the embodiment of the present invention can be preferably carried out by the metal powder production apparatus 10. The metal powder manufacturing apparatus 10 and the metal powder manufacturing method according to the embodiment of the present invention directly injects the cooling medium 22 toward the frame jet 21a including the molten metal powder obtained by the injection of the frame jet 21. The molten metal powder can be cooled rapidly or indirectly, and a metal powder can be obtained. At this time, when the injected cooling medium 22 is heated by the molten metal powder or the frame jet 21a and evaporates, the heat of vaporization is taken away, so that the molten metal powder can be efficiently cooled. Moreover, by injecting the cooling medium 22 having a temperature near the boiling point, the time during which the cooling medium 22 is heated to the boiling point can be shortened, and the cooling rate can be further increased. Moreover, since the flame jet 21a containing the molten metal 1 flows at a supersonic speed or a speed close to the sonic speed, it is considered that the heat transfer is accelerated by the flow velocity, and the cooling rate is further increased. Thus, since the metal powder manufacturing apparatus 10 and the metal powder manufacturing method of the embodiment of the present invention can rapidly cool the molten metal powder, the temperature and amount of the cooling medium 22 to be injected are adjusted. Thus, an amorphous metal powder can be easily obtained.

  The metal powder manufacturing apparatus 10 and the metal powder manufacturing method of the embodiment of the present invention can increase the contact area with the molten metal powder and the frame jet 21a by using the cooling medium 22 of liquid mist. , Evaporation can be promoted to increase the cooling rate. Further, by vigorously injecting the liquid cooling medium 22 with a straight water flow, the cooling medium 22 can be supplied to the inside of the frame jet 21a containing the molten metal powder, and the molten metal powder distributed inside the frame jet 21a. Can be rapidly cooled without unevenness, and a uniform metal powder can be obtained.

  The metal powder manufacturing apparatus 10 and the metal powder manufacturing method according to the embodiment of the present invention are configured so that the temperature of the cooling medium 22 is maintained so that the metal powder immediately after cooling by the cooling medium 22 maintains a temperature higher than the boiling point of the cooling medium 22. In addition, since the cooling medium 22 is jetted while adjusting the amount, the cooling medium 22 does not remain as a liquid after the molten metal powder is cooled. For this reason, the dried metal powder can be obtained. Note that by using liquid nitrogen or liquefied carbon dioxide as the cooling medium 22, a dried metal powder can be obtained even when the molten metal powder is cooled to room temperature. Thus, according to the metal powder manufacturing apparatus 10 and the metal powder manufacturing method of the embodiment of the present invention, since the metal powder can be obtained in a dried state, a dehydration and drying process is unnecessary, Costs related to the process can be reduced. Further, the high-pressure pump used in the water atomization method and the SWAP method is not necessary, and the equipment cost can be reduced. As described above, the metal powder manufacturing apparatus 10 and the metal powder manufacturing method according to the embodiment of the present invention can cool the molten metal powder rapidly and reduce the metal powder at a lower cost than the water atomization method and the SWAP method. Can be obtained.

  In the metal powder manufacturing apparatus 10 and the metal powder manufacturing method of the embodiment of the present invention, the frame jet 21 collides with the molten metal 1 with substantially uniform jet pressure without any gap along the outer periphery of the molten metal 1. Uniform atomization is possible with respect to the molten metal 1, and a fine and uniform spherical metal powder can be obtained.

  In addition, the metal powder manufacturing apparatus 10 and the metal powder manufacturing method of the embodiment of the present invention are provided so that the supply means 11 can continuously supply the metal wire material downward, and each jet burner 12 is made of metal. You may be comprised so that the flame jet 21 may be injected with respect to a wire. In this case, the molten metal can be pulverized while melting the metal wire by injecting the high-temperature frame jet 21 onto the metal wire. The material of the metal wire is, for example, stainless steel, carbon steel, Fe—Si—B alloy, or the like.

  The metal powder production apparatus 10 shown in FIG. 1 is used to produce metal powder using a molten metal 1 of an Fe-10% Cr-8% P-2% C alloy (% is mass%) as a raw material. It was. The temperature of the flame jet 21 injected from the injection means was 1330 ° C., and the drooping speed of the raw molten metal 1 was 2 kg / min. Water was used as the cooling medium 22, and liquid mist was jetted by the cooling means 13. Moreover, the amount of water injection was controlled so that the metal powder immediately after cooling with the cooling medium 22 would be 100 ° C. or higher.

  In addition, since water as the cooling medium 22 has a large specific heat, it can be cooled with a relatively small amount. When the relationship between the amount of water in the cooling medium 22 and the temperature of the metal powder in the metal powder manufacturing apparatus 10 shown in FIG. 1 was examined, the temperature of the metal powder at a position 4 m below the water injection position of the cooling medium 22. Was about 300 ° C. when the water injection rate was 1 liter / min, about 200 ° C. when about 2 liter / min, and about 100 ° C. when about 4-5 liter / min.

  Scanning electron micrographs, particle size distributions and X-ray diffraction results of the obtained metal powder are shown in FIGS. 2, 3 and 4, respectively. As shown in FIG. 2, it was confirmed that a spherical metal powder was obtained. Moreover, as shown in FIG. 3, the metal powder was obtained from a thing with a particle size of several micrometers to more than 100 micrometers, and it was confirmed that the thing with a particle size of 20-30 micrometers is the most. Moreover, as shown in FIG. 4, only a broad halo peak was recognized by X-ray diffraction, and it was confirmed that amorphous metal powder was obtained.

  FIG. 5 shows the result of X-ray diffraction performed for each particle size of the obtained metal powder. In the measurement, the metal powder has a particle size of 53 μm or more and less than 75 μm (sample name “No. 1”), 75 μm or more and less than 106 μm (sample name “No. 2”), or 106 μm or more and less than 150 μm (sample) (Name “No. 3”) and those having a size of 150 μm or more (sample name “No. 4”), and each sample was subjected to X-ray diffraction. As shown in FIG. 5, it was confirmed that the smaller the particle size, the faster the cooling rate, and the more easily amorphous, and the metal powder having a particle size of less than 106 μm is amorphous. In normal water atomization, the particle size can be made amorphous up to about 30 μm, and in gas atomization up to about 10 μm, the metal powder production apparatus 10 can make amorphous even up to a larger particle size. It was confirmed that it was possible.

In addition, other raw materials, for example, Fe-6.7% Si-2.5% Cr-2.5% B-2% C alloy (% is mass) using the metal powder manufacturing apparatus 10 shown in FIG. %), An amorphous metal powder is obtained. From these results, it is considered that the metal powder manufacturing apparatus 10 has a cooling rate of about 10 ^5.4 K / s.

DESCRIPTION OF SYMBOLS 1 Molten metal 1a Hanging downstream 10 Metal powder manufacturing apparatus 11 Supply means 11a Pouring nozzle 12 Jet burner 21 Flame jet 13 Cooling means 13a Cooling nozzle 22 Cooling medium

Claims (10)

A metal powder manufacturing apparatus for obtaining metal powder using the principle of the atomizing method,
Supply means for supplying molten metal or metal wire;
A jet burner for injecting a frame jet to the molten metal or the metal wire supplied by the supply means;
A molten metal powder obtained by jetting the flame jet, or a cooling means for jetting a cooling medium toward the flame jet containing the molten metal powder,
An apparatus for producing metal powder, comprising:   2. The metal powder manufacturing apparatus according to claim 1, wherein the cooling medium is made of liquid or liquid mist.   3. The metal powder according to claim 1, wherein the cooling unit injects the cooling medium so that the metal powder immediately after cooling by the cooling medium maintains a temperature higher than a boiling point of the cooling medium. manufacturing device. The jet burner includes the molten metal or the metal so that the frame jet collides with the molten metal or the metal wire at an acute angle with a substantially uniform jet pressure without a gap along the outer periphery of the molten metal or the metal wire. It is configured to inject the frame jet from around the wire,
The said cooling means injects the said cooling medium from the outer side of the said frame jet injected to the said molten metal or the said metal wire, The metal powder production of any one of Claim 1 thru | or 3 characterized by the above-mentioned. apparatus.   The said cooling means injects the said cooling medium from the outer side and / or inner side of the said flame jet containing the said molten metal powder, The metal powder manufacturing apparatus of any one of Claims 1 thru | or 4 characterized by the above-mentioned. .   A method for producing a metal powder for obtaining a metal powder using the principle of an atomizing method, wherein a flame jet is jetted onto a molten metal or a metal wire, and the molten metal powder obtained by jetting the flame jet, or A method for producing a metal powder, characterized in that a cooling medium is sprayed toward the frame jet containing the molten metal powder.   The method for producing metal powder according to claim 6, wherein the cooling medium is made of liquid or liquid mist.   The method for producing metal powder according to claim 6 or 7, wherein the metal powder immediately after being cooled by the cooling medium is sprayed with the cooling medium so as to maintain a temperature higher than a boiling point of the cooling medium. From the periphery of the molten metal or the metal wire so that the frame jet collides with the molten metal or the metal wire at an acute angle with a substantially uniform jet pressure without a gap along the outer periphery of the molten metal or the metal wire. Jet flame flame,
The method for producing metal powder according to any one of claims 6 to 8, wherein the cooling medium is sprayed from the outside of the frame jet sprayed onto the molten metal or the metal wire. The method for producing metal powder according to any one of claims 6 to 9, wherein the cooling medium is sprayed from outside and / or inside of the flame jet containing the molten metal powder.

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